Women in abdominal compared to femoral adiposity phenotypes have been suggested to have a hormonal pattern that is associated with increased risk of breast cancer. Studies of endogenous sex hormone levels and body fat phenotypes are limited in Caucasian women, and even more so in African-American (AA) women. AA women are to have higher prevelances of obesity and abdominal adiposity, and have a higher premenopausal breast cancer rate than Caucasian women. Using a cross-sectional study desing, this study aims to determine the relationship between serum sex hormones levels and body fat phenotypes in premenopausal AA women. Only eligible AA women with abdominal adiposity defined as a waist to hip ratio (whr) of >0.85, and femoral adiposity with a whr=,0.75 will be recruited into the study to ensure that we will have sufficient numbers within each adiposity phenotype to test our specific aims. Serum levels of total estrone, estrone sulfate, estradiol, free estradiol, androstenedione, testosterone, and free testosterone, as well as sex hormone binding globulin, will be measured on two consecutive mornings during the follicular phase of the menstrual cycle (days 4-7). Body fat phenotype will be determined by anthropometry, and using a total body Dual Energy X- ray Absortiometry (DEXA) scanner. Percent body fat wil be determined using skinfold measurements, total body dexa scanner, and the bioelectrical impedance analysis (BIA) method. This study will provide important data in the possible identification of body fat phenotype as a marker of hormonal pattern associated with increased risk in the developement of breast cancer in premenopausal AA women.